In the fabrication of integrated circuits the silicon wafers on which circuits are formed must undergo a large number of processing steps. For example, each wafer must be coated, exposed, developed, etched and recoated many times as the integrated circuits on the wafers are built up layer by layer. For many of these processing steps the wafer must first be aligned before being placed at the work station for processing. Thus, in many wafer handling systems the wafer is transported to an alignment station and then after alignment transported to the work station.
After alignment it is most important that the wafer be delivered to the work station without disturbing its previously aligned condition. The present invention relates to a chuck assembly for accomplishing the foregoing.